The present invention relates generally to microwave signal processing systems, and specifically to an apparatus that permits both: independent channelized signal processing, and also operation at carrier frequencies that lie within the stopbands which separate the signal channels.
Channelized microwave assemblies commonly divide a comparatively broad microwave band into a plurality of smaller bands which are conducted on separate channels to a destination, then recombined into the original broad microwave band. Because the signal processing in each channel must be independent, i.e., have minimal effect upon the signal in adjacent channels, the multiplexers usually possess stopbands or "holes" near the crossover frequencies in order to maintain sufficient channel isolation.
The mechanization described above works well for most applications. However, there are specific instances where it is desirable to employ signal processing at the stopbands or holes in the frequency spectrum. Unfortunately signal processing at the stopbands is prevented by the conventional systems, since phase tracking is not maintained between channels separated by the stopbands.
In view of the foregoing discussion, it is apparent that there currently exists the need for a signal processing system which permits operation in the stopbands separating independent signal channels. The present invention is intended to satisfy that need.